Screw-cutting die



(No Model.)

T. L. SMITH.

V SCREW (HITTING DIE.

No. 399,707. Patented Mar. 19, 1889.

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lINl-TJEID States Patent Orrncn.

THOMAS L. SMITH, OF REEDSBURG, WISCONSIN, ASSIGNOR TO THE PRATT & WHITNEY COMPANY, OF HARTFORD, CONNECTICUT.

SCREW/CUTTING DIE.

SPECIFICATION forming part of Letters Patent No. 399 ,70'7, dated March 19, 18189.

Application filed August 30, 1887. Serial No.i248,24:0. (No model.)

To all 1077,0721, it may concern.-

Be it known that I, THOMAS L. SMITH, of Reedsburg, in the county of Sauk, and in the State of \Visconsin, have invented certain new and useful Improvements in Screw-Cutting Dies; and I do hereby declare that the following is a full, clear, and exact description thereof.

This invention relates to that class of screwcutting dies having adjustable and renewable chasers, and has for its object to furnish an improved die of that class in which the chasers are removably held in place by means of screws located within the adjusting-ring and set oblique to the side of the chaser, whereby said screws are accessible from the front of the tool and without moving the adj ustingring, as hereinafter more fully set forth.

In the drawings accompanying and forming a part of this specification, Figure 1 is a front view of a screw-cutting die embodying my improvements. Fig. 2 is a section 011 line 2 2, Fig. 1. Fig. 3 a section on line 3 3, Fig. 1. Fig. at is a section 011 line a at, Fig. 5. Fig. 5 is a view of the back side of the tool. Fig. 6 is a plan view of a die-stock for holding my improved die.

Similar reference-characters indicate the same parts in the several figures of the drawings.

The body of the die or the collet, which carries the series of chasers, is designated by A, and is usually bored, as shown, to permit the passage through it of the bolt to be threaded. The chasers B are carried in a series of slots, Z), substantially radially disposed in the front of said collet A, and are provided each with a longitudinal groove (1 in one side thereof. Inclined set-screws c are fitted into inclined holes formed in the collet A, within the chaser-adjusting ring 0, and accessible from the face or front of the die, as shown in Figs. 1 and 3. The said groove (1' is preferably V-shaped, so that the setscrew may be flat-pointethas shown, and bear against one side thereof, as shown in Fig. 3. The chasers are adjusted by the ring O, which fits a thread formed on the collet, as shown in Figs. 2, 3, and a. Screwing said ring farther into the collet (the thread thereof being right-handed) serves to force the chasers inwardly, under the pressure of the setscrews, while to turn the ring oppositely permits the chasers to be forced outwardly by the piece being threaded, or by other means. The ring 0 should be provided with wellknown means (not shown) for temporarily fixing the same firmly on the collet. By this means, and by loosening the screws 0, the chasers may be taken out, reground, and replaced, without disturbing the adjustment. Where large numbers of pieces are to be uniformly threaded, this feature becomes very important, and it is for this class of work that the present improvement is especially designed and used.

The die may be used by inserting it within the holder E of the die-stock and securing it by the screws F, or it may be held in an ordinary screw or bolt machine. I usually form passages a in the collet A, for the purpose of permitting the rcadier escape of chips.

The operation of cutting a thread is carried out in the usual manner, the chasers being first set to the required position radially of the collet by the means described or by other well-known devices therefor, not shown herein, but shown in prior Letters Patent.

Having now fully described my invention, what I claim is 1.. The coi'nbination, in a screw-cutting die of the class specified, of the collet having radially disposed chaser receiving slots, chasers in said slots, each having a groove longitudinally on one side thereof, and setscrews set obliquely in said die-body and bearing against the chasers in said grooves, said screws being accessible from the face of the die, all substantially as described.

The combination, in a screw-cutting die, of the die-body A, chasers 13, having the V- shaped groove (1, and the set-screws c, bearing against the rear face of said groove, all arranged and operating substantially as shown and described.

In testimony that I claim the foregoing I have hereunto set my hand, at Milwaukee, in the county of Milwaukee and State of \Vis cousin, in the presence of two witnesses.

THOMAS L. SMITH.

Vitnesses:

H. G. UNDERwooD, N. E. OLIPHANT. 

